False positive "proc macro not expanded" error when using any derive helpers

[jonas-schievink]

#[derive(serde::Serialize)]
#[serde(rename = "abc")]
struct S;

This reports an error on the #[serde] attribute with "proc macro serde not expanded: proc macro not found", even though the code is valid.

[Veykril]

Ah this is probably caused by this branch

rust-analyzer/crates/hir-def/src/nameres/collector.rs

Lines 1138 to 1150 in 817f46b

	_ => {
	self.def_map.diagnostics.push(DefDiagnostic::unresolved_proc_macro(
	directive.module_id,
	MacroCallKind::Attr {
	ast_id,
	attr_args: Default::default(),
	invoc_attr_index: attr.id.ast_index,
	is_derive: false,
	},
	None,
	));
	return true;
	}

Actually no, we shouldn't hit this here huh

[Veykril]

Actually I can't reproduce this.

Edit: Huh I can in r-a, but not in a standalone project?